Light beam alignment system

Description

1. Field of the Invention

[0001] The present invention relates to a saw having a light source alignment system that does not require internal batteries to power the light source.

[0002] More in particular, the present invention relates to an arbour according to the preamble of claim 1. Such an arbour is known from U.S. Patent No. 5,862,727.

2. Background Art

[0003] Miter saws, portable circular saws, radial arm saws, chop saws, and compound saws are used to precisely cut wood and other materials. For example, miter saws and compound saws are used to cut baseboards, crown moldings, cove moldings, and a wide variety of trim pieces and structural members to exact dimensions. Such circular saws generally have a blade that is rotated at a high rate of speed to cut workpieces. The blade is guarded by a retractable blade guard that covers the saw blade but is retracted as the blade is brought into contact with a workpiece. The workpiece is retained on a base and a turntable that, in conjunction with a fence, are used to position the workpiece to be cut by the saw.

[0004] Before cutting, workpieces are generally marked with a pencil at the intended cut location according to precise measurements to assure accuracy. A common problem with these types of saws is that it takes considerable skill and attention to consistently align the workpiece with the saw blade so that the edge of the saw blade cuts the workpiece at the desired location. With prior art saws, it has not been possible to know if the saw alignment is proper until the saw begins to cut the material. The workpiece may be ruined if it is not set up at the correct orientation when the saw blade contacts the workpiece.

[0005] A laser arbour for a circular saw has been proposed in U.S. Patent No. 5,862,727 to Kelly. The Kelly patent discloses the use of a semiconductor laser arbour for a circular saw that is actuated by a centrifugal switch and directs a line of laser beam on a workpiece. The Kelly patent discloses a battery powered laser light source. One problem with reliance upon batteries is that the semiconductor laser light source draws substantial power from the batteries to illuminate the laser, resulting in limited battery life and requiring frequent battery changes. Similarly, U.S. Patent No. 6,035,757 to Caluori et al. discloses a similar semiconductor laser light beam alignment device for a circular saw having a focusing lens that causes the laser beam to be directed to the blade cut line. The Caluori patent likewise relies upon a battery power source that is carried by the laser arbor. This system has the same problem of limited battery life as the Kelly patent.

[0006] The assignee of this application has marketed a battery power laser alignment device which is described in US 2002 170 404 entitled "Miter Saw Having a Light Beam Alignment System".

SUMMARY OF THE INVENTION

[0007] The battery life problem is solved by the combination of features of independent claim 1.

[0008] According to the present invention, there is provided an arbour as set out in claim 1.

[0009] Preferred embodiments of the invention are set out in the dependent claims.

[0010] According to a preferred embodiment of the present invention, there is provided a saw as set out in dependent claim 6.

[0011] Advantages of the invention over the prior art will be better understood in view of the attached drawings and following detailed description provided below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] 

FIGURE 1 is a perspective view of a sliding compound miter saw having a laser arbour including a power generator for powering the laser;

FIGURE 2 is a schematic fragmentary view of a circular saw blade, laser arbour and blade guard to which a stator for a generator is secured;

FIGURE 3 is an exploded perspective view of a laser arbour including a fixed induction coil secured to the blade guard and a rotatable induction coil secured within the laser arbour;

FIGURE 4 is an exploded perspective view of a laser arbour including a generator having a permanent magnet stator connected to the blade guard and a arcuate coil section secured within the laser arbour; and

FIGURE 5 is a diagrammatic view of a laser arbour, not falling within the scope of the claims and not according to the invention, having slip ring contacts for providing power to the laser.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Referring now to Figure 1, a saw 10 having a circular saw blade 12 is shown. The saw 10 also includes a base 13 and a turntable 14 that together comprise a supporting table generally referred to by reference numeral 15. A fence 16 is provided on the supporting table 15. A workpiece 18 is placed on the supporting table 15 and held against the fence 16 as the workpiece 18 is cut by the saw 10. An arm 20 connects the motor assembly 22 to the turntable 14. The motor assembly 22 forms a part of the saw head assembly, generally indicated by reference numeral 24. The motor assembly 22 drives the saw blade 12. The saw blade 12 is shielded by a fixed guard 28 and a retractable shield 30. A handle 32 is provided for manipulating the saw head assembly 24.

[0014] The saw 10 shown in the illustrated embodiment is a sliding compound miter saw having a miter angle adjustment mechanism 38 and a tilt adjustment mechanism 40. While the illustrated embodiment is of a sliding compound miter saw, the invention is equally applicable to other types of circular saws such as a simple miter saw, a compound miter saw, a chop saw, portable circular saw, or radial arm saw. The saw head assembly 24 is pivotally connected to the arm 20 and includes a spring (not shown) for biasing the saw head assembly 24 normally out of engagement with the workpiece 18.

[0015] When an operator is ready to make a cut with the saw 10, the operator grips the handle 32, depresses the trigger causing the circular saw blade 12 to rotate, and pulls it down toward the workpiece 18. The miter angle adjustment mechanism 38 permits the turntable 14 to rotate relative to the base 13 to change the miter angle of cut. The tilt adjustment mechanism 40 allows the saw head assembly 24 to be pivoted to adjust the inclination of the blade 12 relative to the supporting table 15.

[0016] Referring now to Figure 2, a saw 10 having a laser arbour 42 is illustrated. The laser arbour 42 is mounted adjacent the saw blade 12 on the same spindle 44 as the saw blade. The laser arbour 42 directs a laser beam 48 outwardly from the laser arbour 42 as it is rotated by the spindle 44. The light beam is slightly angled toward the blade preferably at the top surface of the work piece where the blade cuts the work piece. While the light source is described as a laser, another light source such as a light emitting diode (LED) laser, focused electric light bulb based system or other small light could be used with the saw 10.

[0017] Referring now to both Figures 1 and 2, a stator 50 is secured to the fixed guard 28 near the laser arbour 42. The stator 50 may include an electrical magnet or permanent magnet that creates magnetic flux through which the laser arbour 42 is rotated to generate electricity, as will be more fully described below.

[0018] Referring now to Figure 3, one alternative embodiment of the invention is shown wherein a stationary induction coil 52 is included as part of the stator 50 that is mounted on the fixed guard 28. A housing 54 for the laser arbour encloses a rotating induction coil 56. The housing 54 and rotary induction coil 56 are assembled to a laser arbor washer 58 that supports a LED laser module 60. The laser module 60 directs a beam of light through a slot 62 formed on the washer 58. Electricity induced in the coil 56 is conditioned by a conventional inductively coupled power supply circuit of the type commonly used in electric toothbrushes or the like in order to power laser module 60. Stationary induction coil 52 is powered by an AC power source or a pulsed reversing polarity or on-off DC source that induces a corresponding current through the rotating induction coil 56 which is located within the magnetic field of coil 52.

[0019] Referring now to Figure 4, another alternative embodiment is shown wherein a permanent magnet 64 is secured to the fixed guard 28. The permanent magnet 64 is preferably formed by a plurality of arcuate segments (not shown) of a ceramic permanent magnet formed of ferrite or other well-known magnetic ceramic material. A housing 66 is secured to a laser arbour washer 68. An arcuate coil 70 is mounted on the laser arbour washer 68. The coil 70 is rotated with the laser arbour module through the alternating polarity (N-S-N) flux created by permanent magnet 64 thereby generating electricity that is provided to the laser arbour module 72. Laser light is emitted through a slot 74 formed in the laser arbour washer 68.

[0020] Referring now to Figure 5, an example not according to the invention and not falling within the scope of the claims is provided wherein a first set of contacts comprising contacts 80 that are provided on a hub 81 of a laser arbour washer 82 of a laser arbour 84. A housing 85 is provided for enclosing the component parts of the laser arbour 84. Contacts 86 are provided on the spindle 88 that maintain contact with the contacts 80. A pair of slip ring contacts 90 is provided on the spindle 88 at a location spaced from the laser arbour 84. The slip ring contacts 90 connect to contacts 91 and are electrically connected to the contacts 86. The laser module 92 is supported by a laser arbour washer 82 and directs a laser beam through a slot 94 formed in the laser arbour washer 82.

[0021] In each of the embodiments described above with reference to Figures 3-4, no batteries are required to provide power to the laser modules.

[0022] A power conditioning circuit may be provided by a circuit board 96 secured to the washer or could be built-in as part of laser modules. In Figure 3, an AC pulse reversing circuit 98 is illustrated that may be provided as part of the power circuit.

Claims

1. An arbour (42) for mounting on a rotating spindle (44) for rotating a saw blade (12) relative to a non-rotating portion of the saw (10), the arbour (42) comprising:

a housing (54); and

a light source (60; 72) disposed at least in part within the housing, wherein the light source (60; 72) is operable to emit a narrow beam of light (48) from the housing (54) as the arbour (42) rotates to a location adjacent the blade (12) for checking the alignment of the blade (12) with a work piece (18),

characterised in that the arbour (42) comprises an induction coil (56; 70) which rotates with the arbour so as to interact with the magnetic field of a stationary permanent magnet (64) or a stationary induction coil (52) and thereby powering the light source (60; 72) with electrical energy induced in the induction coil (56; 70)

2. An arbour (42) according to claim 1 wherein the induction coil comprises an arcuate coil section (70).

3. An arbour (42) according to claim 1 or claim 2, comprising a power conditioning circuit (96) operable to provide power to the light source (60; 72) within a predetermined voltage range.

4. An arbour (42) according to any one of claims 1 to 3, wherein the rotor (56) is electrically connected to a power conditioning circuit (96) that provides power directly to the light source (60; 72).

5. An arbour (42) according to any one of claims 1 to 4, wherein the light source (60; 72) is a LED laser.

6. A saw (10) comprising a motor (22) having a spindle (44); a blade (12) secured to the spindle (44) and rotatable by the motor (22) to cut a work piece (18); and an arbour (42) as claimed in any one of claims 1 to 5, wherein the housing (54) of the arbour (42) is secured to the spindle (44) for rotation with the blade (12); and wherein the saw (10) comprises a permanent magnet (64) secured to a fixed guard (28) as part of a non-rotating portion of the saw (10) or a stationary induction coil (52) is included as part of the stator (50) that is mounted on the fixed guard (28).

7. A saw (10) according to claim 6, wherein the stationary induction coil (52) associated with a non-rotating portion of the saw (10) interacts with the induction coil (56; 70) of the arbour (42) and thereby powers the light source (60; 72).

8. A saw (10) according to claim 6, wherein the arbour (42) comprises an arcuate coil section (70), the saw comprising a permanent magnet (64) secured to the fixed guard (28).

9. A saw (10) according to claim 6, wherein a power supply circuit (98) for powering the induction coil (52) comprises an AC pulse reversing circuit (98).

Ansprüche

1. Welle (42) zum Anbringen einer drehenden Spindel (44) für das Drehen eines Sägeblatts (12) relativ zu einem nicht-drehenden Abschnitt der Säge (10), wobei die Welle umfasst:

ein Gehäuse (54); und

eine Lichtquelle (60; 72), die zumindest teilweise innerhalb des Gehäuses angeordnet ist, bei der die Lichtquelle (60; 72) zum Aussenden eines begrenzten Lichtstrahls (48) aus dem Gehäuse (54) zu einem Ort benachbart des Blatts betreibbar ist, wenn sich die Welle (42) dreht, zum Kontrollieren der Umgebung des Blatts (12) mit einem Werkstück (18),

dadurch gekennzeichnet, dass
die Welle (42) eine Induktionsspule (56; 70) umfasst, die sich mit der Welle dreht, so dass sie mit dem magnetischen Feld eines stationären Permanentmagneten (64) oder einer stationären Induktionsspule (52) zusammenwirkt und dabei die Lichtquelle (60; 72) mit in der Induktionsspule (56; 70) induzierter elektrischer Energie versorgt.

2. Welle (42) nach Anspruch 1, bei der die Induktionsspule einen bogenförmigen Spulenbereich (70) umfasst.

3. Welle (42) nach Anspruch 1 oder 2, die einen Energieaufbereitungskreis (96) umfasst, der zum Bereitstellen von Energie an die Lichtquelle (60; 72) innerhalb eines vorbestimmten Voltbereichs betreibbar ist.

4. Welle (42) nach einem der Ansprüche 1 bis 3, bei der der Rotor (56) elektrisch mit einem Energieaufbereitungskreis (96) verbunden ist, der die Lichtquelle (60; 72) direkt mit Energie versorgt.

5. Welle (42) nach einem der Ansprüche 1 bis 4, bei der die Lichtquelle (60; 72) ein LED-Laser ist.

6. Säge (10), die einen eine Spindel (44) aufweisenden Motor (22) umfasst; ein Blatt (12), das an der Spindel (44) befestigt ist und das mittels des Motors (22)drehbar ist um ein Werkstück (18) zu schneiden; und eine Welle (42) nach einem der Ansprüche 1 bis 5, bei der das Gehäuse (54) der Welle (42) an der Spindel (44) zur Drehung mit dem Blatt (12) befestigt ist; und bei der die Säge (10) einen Permanentmagnet (64) umfasst, der an einem festen Schutz befestigt ist, als Teil eines nicht-drehenden Abschnitts der Säge (10), oder eine stationäre Induktionsspule (52) als Teil des Stators (50) enthalten ist, der an dem festen Schutz angebracht ist.

7. Säge (10) nach Anspruch 6, bei der die stationäre Induktionsspule (52), die mit einem nicht-drehenden Abschnitt der Säge (10) verbunden ist, mit der Induktionsspule (56; 70) der Welle (42) zusammenwirkt und dabei die Lichtquelle (60; 72) mit Energie versorgt.

8. Säge (10) nach Anspruch 6, bei der die Welle (42) einen bogenförmigen Spulenbereich (70) umfasst, wobei die Säge einen Permanentmagneten (64) umfasst, der an dem festen Schutz befestigt ist.

9. Säge (10) nach Anspruch 6, bei der ein Energieversorgungskreis (98) zum Versorgen der Induktionsspule (52) mit Energie einen AC-Puls-Umsteuerkreis (98) umfasst.

Revendications

1. Arbre (42) destiné à être monté sur une broche rotative (44) pour faire tourner une lame de scie (12) par rapport à une partie non rotative de la scie (10), l'arbre (42) comprenant :

un boîtier (54) ; et

une source de lumière (60 ; 72) disposée an moins en partie dans le boîtier, la source dé lumière (60 ; 72) pouvant être employée pour émettre un faisceau de lumière étroit (48) depuis le boîtier (54) pendant que l'arbre (42) tourne jusqu'à un endroit adjacent à la lame (12) pour contrôler l'alignement de la lame (12) avec une pièce (18),

caractérisé en ce que l'arbre (42) comprend une bobine d'induction (56 ; 70) qui tourne avec l'arbre de façon à interagir avec le champ magnétique d'un aimant permanent statique (64) ou d'une bobine d'induction statique (52) et ainsi alimenter la source de lumière (60 ; 72) avec l'énergie électrique produite dans la bobine d'induction (56 ; 70).

2. Arbre (42) selon la revendication 1, dans lequel la bobine d'induction comprend une portion de bobine arquée (70).

3. Arbre (42) selon la revendication 1 ou 2, comprenant un circuit de conditionnement de puissance (96) utilisable pour fournir de l'énergie à la source de lumière (60 ; 72) dans les limites d'une plage de tension prédéterminée.

4. Arbre (42) selon l'une quelconque des revendications 1 à 3, dans lequel le rotor (56) est connecté électriquement à un circuit de conditionnement de puissance (96) qui fournit de l'énergie directement à la source de lumière (60 ; 72).

5. Arbre (42) selon l'une quelconque des revendications 1 à 4, dans lequel la source de lumière (60 ; 72) est un laser à diode électroluminescente.

6. Scie (10) comprenant un moteur (22) comportant une broche (44), une lame (12) fixée sur la broche (44) et pouvant être mise en rotation par le moteur (22) pour couper une pièce (18), et un arbre (42) selon l'une quelconque des revendications 1 à 5, dans lequel le boîtier (54) de l'arbre (42) est solidaire de la broche (44) pour tourner avec la lame (12), et dans lequel la scie (10) comprend un aimant permanent (64) solidaire d'une protection fixe (28) faisant partie d'une partie non rotative de la scie (10) ou une bobine d'induction statique (52) fait partie du stator (50) qui est monté sur la protection fixe (28).

7. Scie (10) selon la revendication 6, dans laquelle la bobine d'induction statique (52) associée à une partie non rotative de la scie (10) interagit avec la bobine d'induction (56 ; 70) de l'arbre (42) et alimente ainsi la source de lumière (60 ; 72).

8. Scie (10) selon la revendication 6, dans laquelle l'arbre (42) comprend une portion de bobine arquée (70), la scie comprenant un aimant permanent (64) solidaire de la protection fixe (28).

9. Scie (10) selon la revendication 6, dans laquelle un circuit d'alimentation électrique (98) pour alimenter la bobine d'induction (52) comprend un circuit d'inversion d'impulsion alternative (98).

Drawing